This invention relates to a lubrication mechanism in a parallel dual-shaft type gear transmission having an intermediate plate arranged between a transmission case and an extension housing.
Generally, in a parallel dual-shaft type gear transmission, a lubricating oil stored in the transmission case is lifted by the rotation of counter gears mounted on a counter shaft arranged at a lower portion of the transmission case, and is supplied to desired areas to be lubricated. A small diametrical gear, normally a first counter gear of the counter gears, may lift a small amount of the lubricating oil, thereby reducing the lubricating effect to the area to be lubricated accordingly.
To cope with this insufficient lubrication by the prior art, the amount of lubricating oil in the transmission case is increased or a special part such as an oil receiver is used. Further, there is described in Japanese Utility Model Laid-open No. 52-32675, a multiple oil passage formed in the intermediate plate arranged between the transmission case and the extension housing, so as to facilitate the supply of lubricating oil to areas where insufficient lubrication occurs.
In the aforementioned prior art, it is required to increase the amount of the lubricating oil or additionally provide a special part such as an oil receiver. In another case, considerable modification of the intermediate plate is required. As a result, the gear transmission is complicated in structure, and manufacturing costs are increased.